As our society becomes more mobile and simultaneously dependent upon electronic devices, it has been a natural progression for portable electronics to proliferate. This has given rise to a need for portable power sources that can be carried with these electronic devices during their portable use. Still further, because presently commercialized batteries are normally limited in capacity with respect to reasonable and expected use of such devices, industries have turned to rechargeable "battery packs" that may be charged between uses thereby obviating the need for frequent battery replacement.
One such area or industry which is enjoying a substantial increase in the incorporation of rechargeable battery packs is found in powered hand tools. A well known and common example is the battery powered rotary screw-driver having a rechargeable battery pack housed within the handle of the tool which may be "docked" in a charging stand. When the tool is not in use and is docked in the stand, the incorporated battery is being recharged for later use. Obviously, there must be a source of power for this recharger and therefore these rechargers are found at locations with power plug facilities. Because of the portable nature of these tools, it is not always convenient to return to such a stationary recharging unit. Instead, it has been recognized as a particularly beneficial aspect to have the capability to recharge such tools while they are being carried on a vehicle, but not in actual use.
The problem arises in that a ready power source is often not available on such a vehicle, and particularly when the vehicle is stationary with the engine stopped. In such a situation, the generator provided in the vehicle to power accessories and recharge the engine's battery is not operating unless the engine is running. Therefore, limited capabilities for recharging such portable tools places constraints on their use in truly remote locations or over extended periods of time when away from a stationary charging unit.
With the proliferation of communication devices such as cellular telephones and pagers that are battery powered, the necessity for recharging units has become even more important. Both types of these communication devices are often used in automobiles and for extended periods of time away from typical locations where stationary recharging units would be maintained. As an example, a cellular telephone user will often be away from their office for the entirety of a day and reliant upon pre-charged battery packs for powering the telephones. As a result, the need for portable recharging facilities is becoming ever more important and is expected to increase even more so with the increase in portable personal computers that are also often used at remote locations on battery pack power.
As a result of these needs for recharging capabilities at remote locations and on transporting vehicles, the present invention has been developed and designed to remedy the identified deficiencies and satisfy the consumer's needs.